Signs of ancient megatsunami could portend modern hazard

phys.org ^ | 10-02-2015 | Provided by: Columbia University

[JoeProBono]

[JimSEA]

I certainly won’t deny that some studies use ridiculous fear claims to justify themselves and get grant money. Others however will tell you where and how to build and assess possible hazards. Prediction is the ring to grab for as it’s what will save lives.

[Boogieman]

"The researchers say an 800-foot wave engulfed an island more than 30 miles away."

Killer wave! Surf's up brah!

[SunkenCiv]

Thanks Red Badger, will ping later to two lists.

http://www.freerepublic.com/tag/cumbrevieja/index

http://pubs.usgs.gov/ds/2006/171/data/cruise-reports/2001/html/24.htm

[PIF]

The difference between the so-called mega-tsunami and a regular one: Regular ones are caused by a shift up or down in the seafloor. The wave generated rides on the ocean surface and breaks on hitting shore like any other wave, except that it has more power and force - and so does major damage. The so-called mega-tsunami however is generated by debris sliding into the ocean, displacing the water, forcing it up. This wave travels from the bottom up, rather than riding on the surface. The height of the wave is determined in part by the volume of debris. This wave only breaks on hitting land higher than itself - it will ride over all land lower than it is. Thus, an 800 foot tall wave will keep going until it hits land that is 800 feet or more. A regular tsunami will push objects over which it flows in the same direction it is traveling. A so-called mega-tsunami will rip and scour anything in its path. For instance a regular tsunami could leave a building intact or moved off its foundations. A mega-tsunami, on the other hand, will leave nothing of the house, not even its foundation having stripped the land down to bedrock - like the house, and all around it never existed. See: Lituya Bay, Alaska 1958

[SunkenCiv]

Thanks Red Badger.

[SunkenCiv]

Thanks Red Badger.

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[null and void]

I live in NE Kansas. Tsunamis are not high on my list of concerns.

Yet...

[gnarledmaw]

Cascadia subduction zone ... its just a matter of time.

[gleeaikin]

I note in the article they suggest an age of about 73,000 years and a range of 65,000 to 124,000 years ago. Isn’t it interesting that the Toba megavolcano has an age of 74,000 years ago approximately. Could there have been a common cause or interaction between the two disasters?

[gleeaikin]

Looking at the picture of the island I would say that this was a case of an eruption with half the side sliding off into the sea. I found a photo of this with the kilometer shown by comparison. The new volcano has a diameter of almost 1/2 kilometer. That means the caldera is 10 to 12 kilometers in diameter or 6 to 8 miles in diameter. Pinatubo left a crater 3 miles in diameter by way of comparison.
https://en.wikipedia.org/wiki/Pico_do_Fogo

[Red Badger]

See post #25..............